It is well known to produce esters such as ethyl acetate or n-butyl acetate by reaction of ethanol or n-butanol respectively with acetic acid in the presence of an acidic catalyst. However, in the co-production of esters the formation of n-butyl acetate from n-butanol and acetic acid, difficulty is experienced in driving the reaction to completion thereby resulting in an n-butyl acetate product which is contaminated with n-butanol. It is also known to co-produce these esters in a single reactor by operating the reactor sequentially, ie by first producing one ester by reaction of the acid with the first alcohol and then in a swing operation changing over to the second alcohol to produce the second ester. In all of these reactions involving the use of a mixture of alcohols for esterification, it is important to use relatively pure reactants for reaction with acetic acid. This is particularly important if the esters are co-produced in a process for the simultaneous rather than the sequential production of both the esters. The use of reactants of high purity may not be economic commercially for it would significantly add to the cost of producing the esters. It has hitherto been relatively difficult to co-produce simultaneously a mixture of these esters from a relatively impure set of reactants. This is due to the following reasons. For instance, if the ethanol reactant is contaminated with impurities comprising carbonyl compounds such as eg crotonaldehyde, methyl ethyl ketone and the like, it is very difficult to separate the eventual ester product from the impurities. For instance, crotonaldehyde--whilst having a boiling point distinctly different from ethyl acetate--not only has an inordinately large impact on the odor of the ester product, even if present only in very small amounts, but also causes excessive fouling of the reaction column thereby resulting in a high boil-out frequency. On the other hand, methyl ethyl ketone has a boiling point which is very similar to that of ethyl acetate and separation of the two by eg distillation is impractical. Similarly, if the n-butanol reactant is contaminated by butyraldehyde--and this is usually the case if n-butanol is produced by the so called "oxo" process--the boiling point of butyraldehyde is very similar to ethyl acetate and hence cannot be readily separated.